Conventional database systems store data in the form of records or rows. Each row includes one or more related items of information. For example, a row can include the date, number, amount and customer for an order. Certain groups of rows are organized into tables. For example, an Orders table can include all of the rows describing the characteristics of orders that have been received.
Users of database systems manipulate and extract information from the tables and rows that make up the system. Such requests are conventionally referred to as queries. Queries can range in complexity from a request for the display of the information in a particular row to an accumulation of data regarding rows and tables that comprise terabytes of information. Users of database systems also insert, delete, and update the information stored in the tables and rows.
Database systems that employ parallel processing can manipulate and extract information from multiple rows and tables at the same time. Such systems can also insert, delete, and update multiple rows and tables at the same time. Queries and other database system operations that only address a single row at a time do not take advantage of the abilities of parallel processing.